Cisco Firewall :: ASA 5520 - Flags SYN ACK On Interface Dmz1
Jul 12, 2012
I know this issue probably has been beat to death, but I have yet to find the answer to my situation. We recently upgraded from a PIX515e to ASA5520. Shortly after the install I noticed a problem with the servers on our DMZ. This problem was NOT present with our old 515e. The problem is that there seems to be a communication problem between servers on the DMZ, specifically when I try to open the web server homepage from my mail server, I get time-outs. When I ping between the two in either direction, I get time-outs. This might seem trivial, but I have other data servers on the DMZ that need to communicate between themselves.
When we question the tech that performed the install, his answer was that there might be a problem with the switch the servers are connected to, or the servers might have a virus. He stated the process of ping should never involve the DMZ interface. And yes, our DMZ interface IP is the gateway for the servers. Now, if the DMZ (ASA) should never come into play with a ping, why when I turned on logging did I receive the error below? It sounds to me that the ping is going through the interface. Here are a few of the errors on the DMZ with the specific server IPs.
july 13 2012 12:50:04 106014 10.10.0.10 10.10.0.5 Deny inbound icmp src dmz1 10.10.0.10 dst dmz1 10.10.0.5 type 8, code 0
The ping problem was only used as an example the demonstrate that there is a comm problem on the DMZ. ASA is running in router mode.
I have an issue were thousands of connections on the ASA are marked with flags E, below is a visual of the connection. Any ideas what could cause this marking? Also, I can't grasp what the meaing of an outside back connection (ie flags E).
I would like to understand someting about the behaviour of ASA with our traffic scenario and the management of tcp sessions.
1) In particular we noticed that we have connections with the flags Fin without any acknowledgement. The session is silent (the bytes counters aren't incremented) but it remains in the session table as an established connection with the idle timeout of an established conn.
We have about 20% (60K on 300K total) of conns in this state: at our eyes it seems to be an incorrect behaviour...
2) On the connections considered as half -closed we have received an ack to the fin (r or R flag is present), we would like to set the idle timeout to a value lower than 5 minutes but we were not able to reach that result
timeout pat-xlate 0:00:30 timeout conn 0:10:00 half-closed 0:05:00 udp 0:02:00 icmp 0:00:02 ! access-list timeoutClass extended permit tcp any any eq www access-list timeoutClass extended permit tcp any any eq 8080 class-map timeoutClass match access-list timeoutClass class timeoutClass
3) And this type of conns with a Fin on both side that I'm not able to understand... with an ack on one of the side how can I have the other fin??
I have ASA 5510 with 8.2.4 and 8.0.x OS and all seem to have common problem of idle TCP connections not timing out. The host to host connections are coming over VPN tunnels. I have default timeouts on all the firewalls. I have tried changing global timeouts and as well as host specific timeouts using MPF but doesn't work at all ! The problem is when TCP connections are sitting idle in conn table for days and when connection limit of 50,000 conns reach the firewall starts behaving unpredictably dropping packets or unresponsive! I need the unused idle connections to timeout which is NOT happening either by changing global values or MPF.
I have 2 cisco routers that resired on the same interface on Cisco ASA. For security reasons, on both of the routers I have configured default gateway to be ASA interface, then static route between them on the ASA, I get the following error when on station comming from first router trying to connect to another station behind secound router (again, on the same interface, maybe this is the issue?).
ASA-3-106001: Inbound TCP connection denied from flags SYN
There is access list allowing traffic between but hit count is 0
We have a block of addresses assigned to us by our ISP. We need to assign one of these addresses to a vendor we use for traffic to one of their internal devices. Lets say the address we gave them out of that block of addresses is 1.2.3.4
How do I add that address to the outside interface so that when traffic s sent to it that the traffic actually gets to the ASA as right now when we send traffic to that address it doean't make it to the ASA.
I cannot seem to ping from the outside of my 5520 firewall to an inside network. I have a single physical outside interface connected to a Layer 2 switch, with a laptop connected to it. This is on network 10.11.131.0/28. From there, I cannot ping to the inside interface (which is a sub interface on G0/0) with network 10.11.130.0/24/ For some reason, it doesnt work.
Now. I had access-lists in place, but have removed them for testing and it still doesnt work. I have set the security level of inside and outside to 100, and entered the same-security-traffic permit inter-interface command - still no joy. Below is the relevant configuration.
Recently our network experience a Internal DoS attack. One internal server ( the network/security team doesnt have any access to the adninistration of these server) starts to send a lot of DNS bogus request to some DNS servers on the Internet. With sh conn detail we saw the IP of these server and blocked it with an ACL in the Internal ASA 5520 interface. After that, the server team disconnect the server, and made their job cleaning these infected device. Everything goes normal again....
Today, the same server starts again with the same problem. But a lot worst thant the first time. The ASA starts to drops packets in the internal interface, the overruns was increasing dramatically ( like 10000 per second), the asp-drop table shows the same amount of traffic than interface overruns in the ACL-Drop line , and the CNT blocks for 16xxx with sh blocks was in zero. The sh acess-list INSIDE shows near 9 million hints in the line that deny the DNS request from the server to the Internet. Again, we disconnect the server and the problem was solved by the server team.
It seems that our ASA cant handle in their internal interface the amount of traffic that these server send outbound. IS there anyway to raise the blocks in the firewall? What is the best way to deny the servers connections ( ACL, or MPF or threat detection maybe), and avoid the ASA interface overruns even when the server sends these large amount of request.
i have a Problem with SNMP on the ASA Outside Interface. I want to monitor the Interface via SNMP (linkup, link down). I have a Active/Passive Cluster running on 8.4.2 and configured SNMP (v1) for Test on the Outside Interface. It's not that hard but when i try to test my Configuration with (peerless) SNMP Tester the Interface doesn't respond. Did i forget to configure something? Searched the forum but didn't find anything useful.
On a Cisco ASA 5520. I have 2 interfaces that are the same security level. I need hosts on 1 of these interfaces to be able to get to a specific IP and port on the other but I DON'T want to blanket enable 'same-security-traffic permit inter-interface" I have added an ACL inbound on the interface allowing the desired traffic and inbound on the other for return traffic and it simply doesn't work.
I am currently using g0/3 for failover between my two ASA5520's. I would like to move that to the management interface to free up g0/3 for a second DMZ segment. are there any implications to doing this live other than i would only have a single ASA during the move?
From ASA 5520 we tested the interface failover it not working even the interface are getting monitor .
primary is active.
Manually we shut the outside interface of the primary device configuration is getting reflecting in secondary as outside interface shut. Interface failover not happen.
ii All the interface are getting monitor when we gave command sh failover. even though when we shut outside interface failove not happening.
how to do the interface failover in ASA 8.4 version.
I have inherited an ASA 5520. In doing some auditing of the setup, I have noticed a Static Route that has the inside interface of the ASA as the Gateway IP. I am trying to understand the purpose of this route or why a route would be setup this way.
Example Static Route: Inside 10.xx.31.0 255.255.255.0 10.xx.xx.10 (10.xx.xx.10 is the inside interface of ASA)
We have ASA 5520 firewall.For broadband Internet access, we have T1 Router(edge router provided by ISP) which provides public IP's 198.24.210.224 / 29. We have usable public IP's 198.24.210.226 - 198.24.210.230 with default gateway 198.24.210.225. We assigned 198.24.210.230 255.255.255.0 to the outside interface.
If we connect the ASA 5520 outside interface directly to T1 router, can all packets with destination addresses 198.24.210.224/29 reach the outside interface without using other device like another router or switches?I just assume that only packets with destination address 198.24.210.230(outside interface ip) can reach the outside interface from the edge router.Is it wrong assumption? If it is correct, then is there any way to route all packets with destination address 198.24.210.224/29 to the outside interface?
We already have a subnet defined to inside interface and is in produciton. the default gateway is this interface ip. In that setup now I have to add one more subnet and as the first subnet is been defined in ASA indside interface, I have to assign secondary Ip to the inside interface so that new subnet users can easily reach here and go outside.
We want to achieve a load balancing scenario using Virtual IP on DMZ interface on a Cisco ASA 5520.
The IPs we are going to use on DMZ are 10.15.1.2 and 10.15.1.3
These IPs are going to be NATted to all inside IPs.
Lets say our outside IP is X.X.X.X
This IP points to 10.15.1.2 and 10.15.1.3 with .2 being the primary and .3 being the secondary. When I hit the outside IP, it should point me to .2 and that .2 should take me to the inside IPs.
I'm trying to route all default traffic from my production environment through my ASA 5520 on the "outside2" interface.The 5520 has a site to site VPN to our DR site on the "outside/inside" interfaces via one ISP. On another ISP, interfaces "outside2/inside2" go to the internet. When I make my 3750 stack default route for the inside2 interface IP I cannot get to the internet. When it is pointed to the inside interface on my 5505, I can.
I get the following errors when I try to open google.com from a production server:Why is the 5520 trying to use the "outside" interface instead of the "outside2" interface to go out?
I'm trying to attach tacacs server (ACS Version 5.2) in server group on ASA 5520 (Version 8.4). When I test connection in ASDM (Version 6.4) between ASA and ACS it fails. The log message on ASA is:
%ASA-2-106016: Deny IP spoof from (10.8.27.126) to 10.8.48.10 on interface inside.
I recently upgraded my 5520 to 9.0.1 IOS. Today I tried to apply a capture to my inside interface referencing a simple ACL and I get this error.
ERROR: Capture doesn't support access-list <capin> containing mixed policies
I also created a capture for the outside interface with a similar ACL and it worked just fine. I can't seem to find anything on the web that gives me a clue to resolving the error above.
I have a Cisco ASA 5520 (Ver 8.2(4)) with all four interfaces in use (Public, Private, DMZ, Local offices) and an IPS module, so there are no spare interfaces. I have used all of Public IP's on the current interface for various services (these need one to one mapping, so I can't port map mainly due to SSL certificate issues) and I need to add another Public IP range. The secondary option on ASA interfaces does not exist as on routers/switches and I need to use an additional non contiguous IP address range for additional services advertised on the Public interface that are NAT'd to be servers in my DMZ.
I have seen an example of adding a static arp on the Private interface to allow a secondary gateway to be used for outbound traffic, but I need to allow 14 new IP addresses to be NAT'd from the Public to DMZ and possibly also for outbound NAT'ing (from either Private or DMZ to the Public). I have a L2 switch between the ISP router and the firewall, so using VLAN's is not an option unless the ISP can be persuaded (highly unlikey) to add the seondary IP's as a sub interface with tagging. Anyway if this was actioned then we would have a massive outage on our current IP range during the transistion.
We have to enable FIPS 140-2 on our ASA5520's for all our IPSEC VPN connections. We currently have failover on our 5520's. I found a lot of information out there but some seems to conflict one another.What are the things I need to look out for - caveats? Does the clients that connect to the VPN had to use different clients once the FIPS was enabled.Do we need to recreate logical interfaces for each physical interface we have?
Currently l have two ASA 5520's in a active/passive failover scenario. Currently the interfaces for the inside and outside are fixed at 100/FULL.I want to repatch them into GigE ports setup as Auto Negotiate.Is there anyway of keeping the connections through the firewall active in this type of scenrio or will l have downtime disconnecting and repatching? or could l possibly disable failover and reconfigure each ?
I have an issue where our ASA 5520 is impacting upload (from LAN to internet) speed. We have a 100Mbps SDSL internet link and only see around 45-50 Mbps on the upload when going via the firewall, download is around 90+ Mbps so that is acceptable. I have tested a laptop connected directly to the internet router and that give near on the 100Mbps up and down speeds, but if I put that laptop on the LAN or directly onto the firewall interface I only see 90Mbps down and 45Mbps up. I have check that the interface speeds/duplex on the firewall, switch and laptop are correct and also checked there are no errors on the ports. I also turned off the IPS and that made no difference. In addition I have checked the CPU during download/upload (max): CPU utilization for 5 seconds = 9%; 1 minute: 3%; 5 minutes: 1%
In theory the 5520 should be able to cope with this throughput:
Cisco ASA 5500 Series Model/License: 5520 Maximum firewall throughput (Mbps): 450 Mbps Maximum firewall connections: 280,000
I have a asa 5520 with an outside and backup interface. I am trying to configure two static nat statements from the inside to the outside and backup interface. Here is what I have configured so far.
I have an ASA 5520 and I'm using Solar winds real time interface tool to monitor the through put of the port. It seems I can never get it to use more than 100mb, where should I check?
I have run a sh int giga 0/1 and it shows the port is 1000mb full duplex and the I have also checked the other end where it plugs into the LAN and this also says the port is running at 1000mb full duplex.
last night I started upgrading our ASA5520 active/standby cluster. Because of lack of memory, I stopped the upgrade process and will continue when the memory modules have arrived... Currently I'm running 8.0(5) on both nodes (Version: Ours 8.0(5), Mate 8.0(5))Whenever I use the "write standby" command on the active ASA, the passive ASA seems to drop it links for a short while. [code]
I have a 5520 VPN that is otherwise correctly configured for access (so I would say). It is in test (external IP x.x.x.10/22) running parallel on an external switch to a Check Point (x.x.x.4/22) that is the live setup.
I can tunnel consistently to the outside interface on its external IP from inside the network, which is probably natural since I'm inside the network making the attempt; however...
When attempting connection from somewhere outside the network, I generally do not get response from the device. If I connect/disconnect from the Check Point VPN first, then I can subsequently get a connection to the ASA. I did actually have one instance of non-massaged connectivity to the ASA, but there was nothing that I did in the configs that would allow me to claim credit for that instance.
So here's the question: Is there a timeout setting that makes the outside interface go to sleep or something? I'm still at the developmental stage where settings that would be obvious trip me up for hours. I verified the routes. the timeout configs are below; I believe they are all default..
We are having Cisco ASA 5540 having Cisco Adaptive Security Appliance Software Version 8.0(5)23 at certain time of moment daily wer are facing latency and packetdrop wherin when I checked for ASA Interface which gives me " Input Errors" on outside interface ,so can any one tell me what are the causes to get input errors on cisco asa outisde interface.
